Inflatable mattress



FIG. 1 is a perspective view of an inflatable mattress, showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right perspective view thereof;

FIG. 5 is a left perspective view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line disclosure in FIGS. 1-7 is for illustrate purposes only and form no part of the claimed design. 

The ornamental design for an inflatable mattress, as shown and described. 